Analysis of hydrogen and impurity outgassing under carbon, boron and beryllium first wall conditions
Hydrogen and impurity outgassing has been analysed by mass spectroscopy after discharges in TEXTOR with carbon and boron/carbon walls, and in JET with beryllium walls. It has been found that the temporal behaviour of hydrogenic outgassing is characterised by a uniform power law t(-n) with n equal to 0.7 +/- 0.1 independent of the wall situation. With carbon walls, the chemical reactivity between the carbon and hydrogen or oxygen leads to large amounts of hydrocarbon and CO outgassing increasing with increasing wall temperature. Boronisation of TEXTOR has decreased the hydrocarbon and CO outgassing by factors of around 2 and 3 respectively. Under beryllium wall conditions in JET, the CO outgassing has almost disappeared.
Bibliographic Reference: Article: 18th European Conference on Controlled Fusion and Plasma Physics, Vol. III (1991) pp. 49-52
Record Number: 199111384 / Last updated on: 1994-12-02
Original language: en
Available languages: en